Surprise, or prediction error responses, are known to reflect expectations based on the individual’s memory of preceding stimuli. For this reason, surprise responses can be used to infer on the memory representations utilized by different subjects. In this paper, we suggest an EEG-based method for extracting an estimate of effective memory capacity based on the correspondence between a theoretical surprise model and electrophysiological single-trial surprise responses. We demonstrate this method on an EEG response, known as the P300 component, recorded while participants were performing a simple auditory task; we show the correspondence between the theoretical and physiological surprise, and calculate an estimate of the utilized memory. The generality of this framework allows it to be applied to different EEG features that reflect different modes and levels of the processing hierarchy. Future studies may use this framework to construct a handy diagnostic tool for a quantitative, individualized characterization of memory-related disorders.
Paper of the month
Tishby’s Lab: Surprise response as a probe for compressed memory state
PLOS Computational Biology 16(2): e1007065. (2020)